This invention relates generally to the management of oil or gas reservoirs and more particularly to a method of controlling the development of such a reservoir.
An oil or gas reservoir is a zone in the earth that contains, or is thought to contain, one or more sources of oil or gas. When such a reservoir is found, typically one or more wells are drilled into the earth to tap into the source(s) of oil or gas for producing them to the surface.
The art and science of managing oil or gas reservoirs has progressed over the years. Various techniques have been used for trying to determine if sufficient oil or gas is in a given reservoir to warrant drilling, and if so, how best to develop the reservoir to produce any oil or gas that is actually found.
One technique has simply used human experience. Individuals have become skilled in studying data obtained from a given reservoir and then applying their experience to make determinations about the given reservoir and how, if at all, to develop it.
Computer modeling techniques have more recently been used. Previous types of reservoir models have been based on linear mathematical analyses using only a few input parameters (e.g., two or three parameters such as reservoir quality, location, treatment rate, etc.). More recently, neural network modeling of reservoirs has been used. Neural network modeling is advantageous because it can develop correlations between a relatively large number of input parameters and one or more output parameters that would be difficult if not impossible to obtain using linear mathematical techniques.
Neural network techniques have been applied to predicting the production from gas storage reservoirs after training the network on previously drilled and treated wells. This prior neural network development has relied on a human expert designing the neural topology or correlation between inputs and outputs and selecting the optimal inputs for the topology. Even using an expert, there is much educated trial and error effort spent finding a desired topology and corresponding optimal inputs. This is time consuming and expensive and must typically be done for each different reservoir, and it requires a highly skilled human expert to provide useful results.
The ability to more quickly and less expensively analyze a reservoir by whatever means is becoming more and more important. Companies that provide goods and services for use in developing oil or gas reservoirs are basing major business decisions on entire reservoir analysis rather than just individual wells for which they may be hired for a particular job. Because these decisions need to be made quickly as opportunities present themselves, there is the need for an improved method of analyzing oil or gas reservoirs and particularly for controlling the subsequent development of reservoirs that appear to be favorable for oil or gas production.